Also, if you work at a larger company and have a Siemens/Unify IP phone on your desk, it's not unlikely that it's connected to OpenScape Voice running on SUSE.

Also, if you work at a larger company and have a Siemens/Unify IP phone on your desk, it's not unlikely that it's connected to OpenScape Voice running on SUSE. (Even if it's not an IP phone, it might be connected to a smaller sub-PBX which itself talks to an OpenScape Voice server.